1. Technical Field of the Invention
This invention related to the field of multi-channel point-to-multipoint local area network communications method and apparatus supporting voice, video and data. It generally applies to shared wired-medium such as, but not limited to, coaxial cable.
2. Prior Art
There is an increasing need for a home backbone network with enough capacity and managed quality-of-service to serve multiple high-definition audio-visual streams as well as other voice, music, and data traffic generated by Internet appliances such as personal computers, printers, media servers, MP3 players, high-definition personal video recorders, wireless LAN (local area network) and wireless PAN (personal area network) access points.
Broadband coax medium has the advantages of ubiquity and intrinsic high bandwidth (in Gbps), especially suitable for such a home backbone network, comparing to other “no new wire” media such as wireless, unshielded twisted-pair telephone wires, or power-line.
Broadband point-to-multipoint multiple access networks using coaxial cable as a medium are described in [1 Dahod] U.S. Pat. No. 4,500,989 “DIGITAL COMMUNICATION SYSTEM” issued to Dahod, [2 Grobicki] U.S. Pat. No. 5,471,474 “COMMUNICATIONS HIGHWAY NETWORK SYSTEM” issued to Grobicki et al., [3 DOCSIS] CM-SP-RFlv2.0-108-050408 “DOCSIS 2.0 SPECIFICATION” available on www.cablemodem.com/downloads/specs/, [4 Terry] U.S. patent application Ser. No. 10/071,007 “MULTI-BAND COAX EXTENDER FOR IN-BUILDING DIGITAL COMMUNICATION SYSTEMS” filed by Terry et al., [5 Gurantz] U.S. patent application Ser. No. 09/910,412 “NETWORK INTERFACE DEVICE AND BROADBAND LOCAL AREA NETWORK USING COAXIAL CABLE” filed by Gurantz et al., [6 Morelli] U.S. patent application Ser. No. 10/852,002 “NETWORKING METHODS AND APPARATUS” filed by Morelli et al., [7 Ophir] U.S. patent application Ser. No. 10/935,963 “IMPLEMENTING A HYBRID WIRELESS AND COAXIAL CABLE NETWORK” filed by Ophir et al., [8 Robertson] U.S. patent application Ser. No. 10/924,077 “FULL DUPLEX WIDEBAND COMMUNICATIONS SYSTEM FOR A LOCAL COAXIAL NETWORK” filed by Robertson et al., [9 Eng] U.S. patent application Ser. No. 10/122,828 “FULL-SERVICE BROADBAND CABLE MODEM SYSTEM” filed by the same inventor of this invention, and [10 Lind] U.S. patent application Ser. No. 10/446,511 “WIDEBAND DOCSIS ON CATV SYSTEMS USING PORT-TRUNKING” filed by Lind et al., each of which is incorporated herein by reference.
[1 Dahod][2 Grobicki] [6 Morelli] disclosed the using of a frequency translator at the root of the coaxial cable topology to reflect upstream transmissions to all stations. [5 Gurantz] disclosed a method of using a non-matching filter to reflect upstream transmissions back to all stations. [4 Terry][6 Morelli][7 Ophir] used spectrum above 750 MHz for upstream and downstream channels to avoid conflict with the spectrum used by conventional cable TV programming channels. [7 Ophir] disclosed a way to use coaxial cable to extend the reach of wireless LAN transmission. [8 Robertson] described a coaxial home network that used channels above 750 MHz for full-duplex point-to-point communications between two stations.
[3 DOCSIS] disclosed the data-over-cable standards for a sub-split hybrid fiber-coaxial (HFC) cable infrastructure with a centralized controller (cable modem termination system, CMTS) residing at the root of the coaxial cable topology with a media-access-control (MAC) for coordinating the forwarding of packets to and from a plurality of cable modems. While [3 DOCSIS] has a robust MAC layer and the intelligence at the headend, and enjoys a consumer level pricing for the large volume of cable modems, it is nevertheless designed for metropolitan area operations for service providers; the CMTS is prohibitively expensive for residential consumer use. Moreover, the MAC is not scalable for providing the capacity for video operations.
[9 Eng] disclosed a multi-channel MAC called fsMAC (full-service MAC) that scales the network capacity of a data-over-HFC network by adding multiple upstream and downstream channels, with a DCPC-UCC (downstream control and payload channel—upstream control channel) control channel-pair for efficient upstream multiple access and high network capacity in both upstream and downstream directions.
[10 Lind] disclosed an enhancement to the DOCSIS MAC for adding wideband downstream and upstream channels to increase the capacity and burst rate of a DOCSIS HFC network.
Using the spectrum above conventional cable TV channels requires changes to the coaxial network. It is not compatible with legacy cable modems and cable set-top boxes (STBs) and increases the complexity and cost to the home networking infrastructure.
Therefore there is a need for an improved, reliable, high-capacity and low-cost broadband local area networking backbone for homes and premises to address the shortcomings of the prior art. It is desirable to take advantages of the legacy cable modem technology while providing the capacity and quality-of-service (QoS) required by multimedia communications of voice, video and data within the premises at consumer-level price.